Increasingly, vehicle manufacturers are installing safety devices in vehicles to enable drivers to drive in a safer more efficient manner. For example, some manufactures have included forward looking systems (FLSs), rear detection systems (RDSs) and side detection systems (SDSs) within certain vehicle models. An adaptive cruise control (ACC) system is one example of a FLS.
A typical ACC system uses a radar sensor (some use laser sensors), mounted at the front of the vehicle, to detect objects in the forward path of the vehicle. If the lane ahead is clear, the ACC system maintains a set vehicle speed. However, when a slower vehicle is detected, the ACC system maintains a driver selected distance (using throttle control and limited braking) between the vehicles. A typical ACC system uses mechanically scanned radar sensors, which normally improves the ability of the system to detect targets (i.e., vehicles) in heavy traffic. A typical commercially available ACC system has a range of 150 meters, an azimuth of 15 degrees and updates at a 10 Hz rate. An ACC system generally determines a range of a detected object, as well as the relative speed of the detected object.
SDSs detect objects that are at a side of a vehicle (i.e., in a driver's blind spot). A typical SDS includes a radar sensor that is mounted in each rear quarter panel of the vehicle. Each radar sensor is designed to detect objects in an adjacent lane. In this manner, the SDS can provide a visual indication to the driver to warn of objects in the driver's blind spot.
An example of an RDS is a back-up aid (BUA) or a reverse sensing system. BUAs may be used as short range parking aids and have included visual and audible alarms to warn a driver of an impending collision. A typical BUA system includes a radar sensor that provides a rear detection range of up to 6 meters. Some BUAs also include ultrasonic sensors that provide bumper coverage. A typical BUA is activated when a vehicle is put into a reverse gear and is useful for backing at higher speeds. A typical park-assist system is useful for parallel parking and backing in and out of parking spaces.
Short-range park-assist systems have generally implemented algorithms that respond based on a distance to a detected object, while longer-range BUA systems have generally implemented algorithms that respond to time-to-collision criteria in determining when to alert a driver. While it is desirable for a BUA system to provide both warning and park assist functions, switching between the functions has the potential for confusing a driver when the system changes between short-range and longer-range functions.
What is needed is a BUA system that provides both warning and park assist functions in a manner that reduces confusion of a driver.